The Petronas towers are located in Malaysia.  They are the tallest towers in the world (as of Jan. 2016).  The Willis Tower's roofline is actually taller, but the antennae on the Petronas Towers are included in the official height since they are considered part of the design, and the Willis Tower antennae are not.

 

 Construction started in 1993 and was completed by 1996.  There are 88 floors, with 5 of them being underground!  The towers are made of reinforced concrete, steel and glass.  Their shape is inspired by Islamic Art.

 

Inside of the towers is a gigantic shopping mall.  Other attractions include an art gallery, a theatre, a science center and an underwater aquarium.

 

 

On the 41st and 42nd floors, there is a double-decker skybride that connects the two towers.  It is the highest 2-story bridge in the world.  Here's the interesting part--the skybridge is NOT connected to the towers!  Instead the skybridge slides in and out of the towers to help prevent it from breaking due to the high winds.